Letters with similar shapes should be distinguished by their heights and levels to avoid them getting mixed up together. Create space around letters so they can appear taller rather than wider for an easier read.
Giving letters unique shapes avoids symmetry between them, which prevents the perception that letters are sliding, turning, mirroring, disappearing, or swapping.
Pay attention to the opening of the letters (e-g), so they can be easily recognisable.
The spacing between letters is important, especially for the letters (o-e-a-u), to prevent them from overcrowding and allow for better differentiation. Additionally, allow for enough spacing between lines to avoid the feeling of all lines blurring.
Distinguish letters such as h and n by elongating and shortening the stems on them, while the ascenders (b-d-f-h-k-l) and descenders (g-j-p-q-y) should be longer.
Make sure letters with lower case that look identical to upper case ones are different enough. For instance, upper case (i) and a lower-case (L). Avoid using all caps for longer blocks of text, as this can lead to confusion about where sentences start and end.
The thickening and bolding of capital letters as well as punctuation helps highlight the start and finish of each sentence. Making it easier for dyslexic people to break sentences up into digestible content.